PROJECT SUMMARY/ABSTRACT Thirty four percent of school-age children are overweight or obese with clear obesity- and cardiovascular (CV)- related health disparities among racial groups. There have been calls to assess novel approaches for prevention of obesity and CV risk, particularly for African-American (AA)/black children. Given their increased risk of short sleep, obesity and CV disturbance, one approach that may be promising for children who are AA/Black is enhancing sleep duration. Observational studies with children demonstrate that short sleep increases risk of obesity and other CV risk factors. Experimental studies with adults document that changes in sleep may influence obesity risk primarily through eating pathways. Our own randomized controlled trials with children 8-11 years old provide a robust signal that enhancing sleep duration leads to decreases in: motivation for food, reported food intake and TV viewing; and increases in physical activity-with a net result of positive changes in weight status and potential changes in glucose regulation, particularly for children who enhance their sleep the most. However, preliminary studies are limited by short study timeframes (2-weeks to 2- months), primary enrollment of non-Hispanic White children, and primary aims focused on eating behaviors rather than obesity or other CV risk. In this competing renewal we propose addressing these limitations by enrolling children who are AA/black, assessing effects of intervention over a 12-month period, and focusing the primary aim on change in zBMI. Specifically, we propose rigorous evaluation of two active preventive interventions: a) enhancing sleep alone (Optimize Sleep [OS]), and b) enhancing sleep along with eating and activity behaviors that have demonstrated efficacy for obesity prevention and are implicated in self-regulatory pathways related to sleep (i.e., energy dense snack foods and beverages, TV viewing, and physical activity) (OS-Plus). The present study proposes to enroll 204 children 8-11 years old who are AA/black, primarily from low socioeconomic backgrounds, and who sleep < 9.5 hours/night into a 12-month study. Children will be randomly assigned to either OS or OS-Plus. Over the 6-month treatment phase, all children will attend an 8- session treatment (4 in-person & 4 phone follow-up) in which they will learn effective behavioral strategies to improve sleep duration (OS) or improve sleep and targeted eating and activity behaviors (OS-Plus); there will be monthly phone contact during the maintenance period (6-12 months). At baseline, end of treatment (6 months), and 12 months, the following will be measured: sleep duration (actigraphy), eating behaviors (24-hour dietary recalls, eating self regulation), physical activity (accelerometry), anthropometrics (height, weight, waist circumference), and additional cardiometabolic risk factors (adiposity, lipids, and glucose regulation). Primary aim is to determine the efficacy of OS-Plus relative to OS on change in body mass index z-score (BMIz) at end of treatment. Secondary aims will assess efficacy of OS-Plus relative to OS on additional cardiometabolic risk factors, eating and activity behaviors. Exploratory aims will assess maintenance of effects at 12 months.